I have set both of my fresh rebuilds at base timing. I am now ready to take them to 34deg. The problem I'm having is the Merc book says 34@4500rpm is that correct is it possible that the motor is still advancing at that high of a rpm? How do you guys set this if it is? I would be running around 65 at 4500 no way would I be in the bilge Free reving is just as scary! And no I am not pulling them to put on a dyno. So any good ideas or do I just keep snaping the throttle on a free rev

HP500 carbs With Merc Thunderbolt 5 module. THANKS Scott

"do I just keep snaping the throttle on a free rev"

You got it. I once was talking to Nickerson about a motor I just finished with his help, when he asked me where I set the timing. I said that since the V-6 module was x degrees timing on a V-8, I set it to 30-x at idle. He said (in a matter of words) "I don't give a crap where it is at idle, I want to know where it is at 4000rpm". I voiced that I had not do that due to my fear of reving it up unloaded. He said get over it. I did and now I do! I wouldn't do it any other way now.

Just watch the timing light, while manually reving the motor while right over it and you will see the mark advance and suddenly stop. I think you will find it happens well below 4500rpm, but it wouldn't hurt to give it several blips to make sure.

V8-24 module is full advance at 3500 the V8-24S is full advance at 5000.The V8-24 you set base timming at 8*then the module adds 24* and you get 32* .you want 34* so you start with 10* base then the module will add 24* and you end up with 34*.I know it sounds like madness sitting with the motor at full throttel but that is what we have done just to speed things up I just watch my hand tac. and when I have found max RPM I back it down then I bring it back up till I hit it again then tighten dis. down then look at where I am in the total *.Most will stop while on the water bump up the timming 2* at a time and find out where the motor is makeing max RPM.say you are at 32*you advance to 34*and you increased by 150RPM then you go to 36* and you did not see an RPM increase you back it back down to 34*.Don't forget you have found max advance and if you feel that you can afford to run it there then run it but if you rather be on the safe side you should back it down .To much advance hurts the motor not enough only hurts performance.